THERMOREGULATION IN ANIMALS. Animals can maintain physiological favorable internal environments via homeostasis mechanisms

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1 THERMOREGULATION IN ANIMALS Animals can maintain physiological favorable internal environments via homeostasis mechanisms

2 Thermoregulation (pg. 262): Thermoregulation= an animals ability to maintain internal temperatures Regulation requires energy, animals must balance gains vs. losses for energy and materials and homeostasis allows animals to keep this balance.

Thermoregulation: Conduction: direct transfer of heat between molecules in direct contact with each other Convection: transfer of heat by movement of air or liquid past a surface wind

3 Thermoregulation: Conduction: direct transfer of heat between molecules in direct contact with each other Convection: transfer of heat by movement of air or liquid past a surface wind chill Radiation: emission of electromagnetic waves (high to low) Evaporation: removal of heat due to water changing from liquid to gas state (cooling effect due to endothermic reaction).

Thermoregulation: Classifying animals based on the role of their metabolism in heat production:

the animal (most invertebrates, fishes, amphibians and reptiles).

than the environment (mammals, birds, some fishes and insects and a few reptiles).

vigorous activity for longer periods of time than ectotherms.

4 Thermoregulation: Classifying animals based on the role of their metabolism in heat production: Ectotherm: has such a low metabolic rate that it contributes a very small amount of heat energy to the animal (most invertebrates, fishes, amphibians and reptiles). Endotherm: high metabolic rate contributes enough heat energy to keep its body considerably warmer than the environment (mammals, birds, some fishes and insects and a few reptiles). Advantages (of endothermy): high levels of aerobic metabolism which allows animals to perform vigorous activity for longer periods of time than ectotherms. Endotherms can also survive in areas of severe temperature fluctuations because of their ability to maintain stable body temps. Disadvantages: High energy costs, endotherms must consume much more food than ectotherms.

Thermoregulation For endotherms and some ectotherms that thermoregulate, there are several physiological and

Adjusting the rate of heat loss from the animal to the environment- using insulation (fat, feathers, hair) or

Cooling through sweating, bathing or panting (evaporative heat loss) 3.

5 Thermoregulation For endotherms and some ectotherms that thermoregulate, there are several physiological and behavioral adaptations that help keep a balance between heat loss and gain. 1. Adjusting the rate of heat loss from the animal to the environment- using insulation (fat, feathers, hair) or physiological mechanisms (vasodilation, vasoconstriction, or countercurrent heat exchange). 2. Cooling through sweating, bathing or panting (evaporative heat loss) 3. Behavior responses- sunning, find cool, shaded or damp areas, hibernation, torpor, estivation, brumation or migration 4. Changing the rate of metabolism and heat production (mainly mammals, see next slide).

Thermoregulation in Mammals/Birds: Mammals and birds

36-38 o C Birds:39-42 o C Must counteract heat loss to

heat instead of ATP (nonshivering thermogenesis NSP) 4.

6 Thermoregulation in Mammals/Birds: Mammals and birds maintain body temps within a narrow range: Mammals: o C Birds:39-42 o C Must counteract heat loss to the surrounding environment 1. Metabolic Heat 2. Muscle activity or shivering 3. Hormones can increase metabolic activity and produce heat instead of ATP (nonshivering thermogenesis NSP) 4. Brown fat (specialized for heat production). 5. Insulation (hair, feathers, blubber)

7 Homeostasis and Thermoregulation

8 REGULATION OF INTERNAL ENVIRONMENT Thermoregulation, osmoregulation and excretion

9 Maintaining solute and fluid balance (pg. 264): Interstitial fluid fills tissue spaces between cells and blood moves to and from tissues. Both of these tissues = extracellular fluid and it must be maintained through homeostasis.

Osmoregulation: management of body s water and solute levels Osmoregulation in Animals: a. Ammonia (aquatic animals) b. Urea (amphibians, mammals, marine fishes) c.

10 Osmoregulation: management of body s water and solute levels Osmoregulation in Animals: a. Ammonia (aquatic animals) b. Urea (amphibians, mammals, marine fishes) c. Uric Acid (snails, insects, birds and reptiles) *Fish- excrete ammonia through gills and kidney only excrete a minor amount of nitrogen wastes *Urea is about 100,000 times less toxic than ammonia so animals can store and transport urea safely at high concentrations * Uric acid is largely nontoxic but it is not soluble in water so it is usually excreted as a paste

Balancing water gain with water loss: Marine

They are isoosmotic to their environments Most marine

11 Balancing water gain with water loss: Marine invertebrates like this hagfish are osmoconformers. They are isoosmotic to their environments Most marine invertebrates, sharks and cartilaginous fishes are osmoregulators. The ocean is a very dehydrating environment because it is much saltier than the internal organs or animals.

12 Balancing salt and water concentrations

Filtration: Collected when water and solutes are forced across a selectively permeable membrane to create a filtrate

13 Animal Excretory Systems: Water balance depends on the regulation of solutes and how they move between internal and external fluids. Filtration: Collected when water and solutes are forced across a selectively permeable membrane to create a filtrate Reabsorption: Substances can be reclaimed from the filtrate before excreted Secretion: Other substance (toxins, drugs and excess ions) from body fluids can enter the filtrate here Excretion: The filtrate leaves the system and the body.

14 Animal Excretory systems:

15 Mammalian Excretion: Mammals have a pair of kidneys that are each supplied with blood by a renal artery and renal vein. Filtration is a result of blood pressure through the nephrons of the kidneys Urine exits through each kidney through the ureters which drain into the urinary bladder. Urine is excreted from the body through the urethra

16 A closer look at excretion: For detailed map: look at page 946

If it gets above 300mOsm/L, ADH is released into the blood stream.

17 Regulation of excretion: ADH or vasopression monitors the osmolarity of the blood. Ex.) After you sweat or eat salty food, that would increase the blood osmolarity. If it gets above 300mOsm/L, ADH is released into the blood stream. Target: Nephrons Response (s): Collecting duct increases water reabsorption, concentrates urine, reduces urine volume and lowers blood osmolarity.

18 Regulation using ADH and RAAS

19 CHEMICAL SIGNALING Regulation through the Endocrine System

Endocrine Glands: hormone-secreting glands that are able to secrete their chemical directly into body fluids Neurosecretory

20 Endocrine System: Hormones secreted by endocrine cells regulate reproduction, development, energy metabolism, growth and behavior. Requires the coordinated efforts of both chemical signaling and neural signaling. Endocrine Glands: hormone-secreting glands that are able to secrete their chemical directly into body fluids Neurosecretory cells: specialized nerve cells that secrete hormones Use your book (pgs ) and the textbook (pg. 961) to find out the endocrine glands responsible for certain hormones:

21 Endocrine glands and organs with endocrine cells: Some endocrine system cells are found in organs that are part of other organ systems. Thymus Heart Liver Stomach Kidneys Small Intestine

22 More info on the endocrine system: Some signaling molecules act within in the body. Pheromones are chemicals that are released into the environment have a variety of uses: Marking territory Warning of predators Attracting mates Landmarks or trails

lipids (insoluble in water) and can easily diffuse across cell and nuclear membranes to

23 Steroid Hormones vs. Protein Hormones Steroid hormones are synthesized from cholesterol, they are soluble in lipids (insoluble in water) and can easily diffuse across cell and nuclear membranes to combine with receptor molecules in the nucleus. Target cells from hormonereceptor complexes in the nucleus and they combine with DNA to trigger transcription and translation

24 Protein Hormones: Protein-based hormones are called peptide hormones. They are made up of amino acids, which are the structural building blocks of all proteins, including the proteins you eat. Peptide hormones tend to be globular, meaning that they have a ball-like shape. They also tend to be water-soluble, meaning they can dissolve in and travel easily through the blood

How does it work? 1. Nervous system monitors environment 2.

4. Hormones reach target organ, which will respond appropriately 5.

25 How does it work? 1. Nervous system monitors environment 2. If problems are detected, nervous system sends messages to endocrine glands or endocrine cells 3. Endocrine glands or cells produce and secret hormones into the blood 4. Hormones reach target organ, which will respond appropriately 5. Homeostasis restored or problem solved and detected by receptors and brain stops sending message to endocrine glands

The hormone called melanocytestimulating hormone (MSH) secreted by pituitary

26 Remember cell signaling? Darkness varies with the organelle arrangement within melanocytes. The hormone called melanocytestimulating hormone (MSH) secreted by pituitary gland will reach a receptor in the plasma membrane and causes rearrangement of organelles and determines spacing. Closer spaced = lighter skin

A couple of examples of regulation by the endocrine system: The Pituitary Gland Anterior Pituitary gland: Hormones of the anterior pituitary: Thyroid Stimulating Hormone (TSH) Follicle Stimulating

27 A couple of examples of regulation by the endocrine system: The Pituitary Gland Anterior Pituitary gland: Hormones of the anterior pituitary: Thyroid Stimulating Hormone (TSH) Follicle Stimulating Hormone (FSH) Luteinizing Hormone (LH) Contains six types of secretory cells, all of which secrete their hormones in response to hormones reaching them from the hypothalamus. Prolactin (PRL) Human Growth Hormone (HGH) Adrenocorticotropic Hormone (ACTH) Alpha Melanocyte-Stimulating Hormone (α-msh)

28 A closer look at HGH HGH is a protein hormone that promotes growth by: Binding to the surface of liver cells Stimulates insulinlike growth factor-1 (IGF-1) which acts directly on the ends of the long bones promoting growth

More with HGH Growth factors are proteins that bind to cell surface receptors and stimulate cell division, cell differentiation or cell proliferation Growth hormone levels are increased by sleep,

29 More with HGH Growth factors are proteins that bind to cell surface receptors and stimulate cell division, cell differentiation or cell proliferation Growth hormone levels are increased by sleep, stress, exercise and low glucose levels in the blood. They also increase around the time of puberty. Growth hormone release is lowered in pregnancy and if the brain senses high levels of growth hormone or insulin-like growth factors already in the blood. This reduction in growth hormone levels is affected by another hormone called somatostatin.

Hypersecretion leads to gigantism In adults, a Hypersecretion of GH or GHRH leads to acromegaly Growth

30 Imbalances of HGH Things that can go wrong: In childhood, Hyposecretion of GH produces a short but normally-proportioned body. Hypersecretion leads to gigantism In adults, a Hypersecretion of GH or GHRH leads to acromegaly Growth retardation can also result from an inability to respond to GH. This can be caused by inheriting two mutant genes encoding the receptors for GHRH or GH (causing Laron syndrome, a form of dwarfism). Gentle Giant

31 ENDOCRINE RESPONSE RESEARCH Your task today: Pick one of the hormones we haven t already highlighted (rememberepinephrine and ACTH) aren t options because we re doing our lab on those tomorrow) Research the following aspects: 1.) What triggers the secretion of that hormone? 2.) Where is it secreted from? 3.) What is the target organ/cell tissue? 4.) What is the immediate target cell response from that hormone? 5.) What body functions are affected? 6.) What are some of the problems that can occur with this specific response? Too much or too little or body doesn t recognize the hormone etc

Stress and the endocrine system Endocrine gland involved: adrenal glands Hormones involved: Epinephrine Norepinephrine ACTH Tropic hormones Corticosteroids Today you will be doing a series of stress

32 Stress and the endocrine system Endocrine gland involved: adrenal glands Hormones involved: Epinephrine Norepinephrine ACTH Tropic hormones Corticosteroids Today you will be doing a series of stress tests to see how your body responds The science behind stress and the endocrine system: Stress is feeling experienced when a person thinks that the demands exceed the personal and social resources the individual is able to use. It is a departure from homeostasis Stressors include: Physical (heat/cold), chemical (anaerobic conditions), physiological (exercise), psychological or emotional (fear/anxiety) or social (personal conflicts)

33 Stress response: Short term stress: initiates release of epinephrine and norepinephrine (adrenal medulla) Long term stress (chronic): the adrenal cortex secretes mineralocorticoids and glucocorticoids aka: flight or fight response

34 Stress can be good (eustress) or bad (distress) but in either case, the body has its limits. Stress Response:

18-21 = 120/79 FEMALES Heart Rates Ages 18-25 Athlete 54-60

36 Normal Systolic and Diastolic pressures: 110/75= Low Normal 120/80 = Normal 130/85 = High Normal Females = 117/ = 120/79 FEMALES Heart Rates Ages Athlete Excellent Good Above Avg Below Avg Poor 85+

37 Top Stressors for Americans:

38 Endocrine Regulation: Stress

Regulation: The Pituitary Gland Posterior Pituitary Gland: This lobe releases two hormones (both of which are made in the hypothalamus) Vasopression or ADH is used to facilitate the reabsorption of

39 Regulation: The Pituitary Gland Posterior Pituitary Gland: This lobe releases two hormones (both of which are made in the hypothalamus) Vasopression or ADH is used to facilitate the reabsorption of water into the blood. Essentially reducing the amount of urine formed. Oxytocin is a protein hormone that causes contractions of the uterus before childbirth as well as stimulating milk production after birth. Also called the BONDING hormone

Chapter 16. Urinary System and Thermoregulation THERMOREGULATION. Homeostasis

Chapter 16. Urinary System and Thermoregulation THERMOREGULATION. Homeostasis Homeostasis Chapter 16 Urinary System and Thermoregulation! Homeostasis Maintenance of steady internal conditions despite fluctuations in the external environment! Examples of homeostasis Thermoregulation